bpo-34623: Use XML_SetHashSalt in _elementtree (GH-9146)
The C accelerated _elementtree module now initializes hash randomization
salt from _Py_HashSecret instead of libexpat's default CPRNG.
Signed-off-by: Christian Heimes <christian@python.org>
https://bugs.python.org/issue34623
diff --git a/Include/pyexpat.h b/Include/pyexpat.h
index 44259bf..07020b5 100644
--- a/Include/pyexpat.h
+++ b/Include/pyexpat.h
@@ -3,7 +3,7 @@
/* note: you must import expat.h before importing this module! */
-#define PyExpat_CAPI_MAGIC "pyexpat.expat_CAPI 1.0"
+#define PyExpat_CAPI_MAGIC "pyexpat.expat_CAPI 1.1"
#define PyExpat_CAPSULE_NAME "pyexpat.expat_CAPI"
struct PyExpat_CAPI
@@ -48,6 +48,8 @@
enum XML_Status (*SetEncoding)(XML_Parser parser, const XML_Char *encoding);
int (*DefaultUnknownEncodingHandler)(
void *encodingHandlerData, const XML_Char *name, XML_Encoding *info);
+ /* might be none for expat < 2.1.0 */
+ int (*SetHashSalt)(XML_Parser parser, unsigned long hash_salt);
/* always add new stuff to the end! */
};
diff --git a/Misc/NEWS.d/next/Security/2018-09-10-16-05-39.bpo-34623.Ua9jMv.rst b/Misc/NEWS.d/next/Security/2018-09-10-16-05-39.bpo-34623.Ua9jMv.rst
new file mode 100644
index 0000000..31ad92e
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2018-09-10-16-05-39.bpo-34623.Ua9jMv.rst
@@ -0,0 +1,2 @@
+The C accelerated _elementtree module now initializes hash randomization
+salt from _Py_HashSecret instead of libexpat's default CSPRNG.
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 02781d5..bba6873 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -3272,6 +3272,11 @@
PyErr_NoMemory();
return -1;
}
+ /* expat < 2.1.0 has no XML_SetHashSalt() */
+ if (EXPAT(SetHashSalt) != NULL) {
+ EXPAT(SetHashSalt)(self->parser,
+ (unsigned long)_Py_HashSecret.expat.hashsalt);
+ }
if (target) {
Py_INCREF(target);
diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
index c8a01d4..c52079e 100644
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -1877,6 +1877,11 @@
capi.SetStartDoctypeDeclHandler = XML_SetStartDoctypeDeclHandler;
capi.SetEncoding = XML_SetEncoding;
capi.DefaultUnknownEncodingHandler = PyUnknownEncodingHandler;
+#if XML_COMBINED_VERSION >= 20100
+ capi.SetHashSalt = XML_SetHashSalt;
+#else
+ capi.SetHashSalt = NULL;
+#endif
/* export using capsule */
capi_object = PyCapsule_New(&capi, PyExpat_CAPSULE_NAME, NULL);